In past years various mechanisms for extracting essential elements from raw plant material have been researched by professional scientists, until recently the extraction of medicinal compounds from cannabis has been limited to small scale extractions by authorized scientists in the academic realm or has been performed clandestinely by individuals operating outside the law.
With the advent of legalizing the medicinal use of cannabis in 16 states the extraction of medicinal compounds from cannabis plant material in large volumes is in demand. The most significant driver for this demand are the increasing bodies of research showing tangible benefits to individuals suffering from a plurality of ailments when using medicinal cannabis. Furthermore no toxic or overdose effects from the use of cannabis have been medically documented.
Cannabis plant material contains tetrahydrocannabinol carboxylic acid (THC—COOH); this substance is also referred to as THC acid, Δ9-THC acid, THCA-A, or THCA.
The Journal of Chromatography article “Innovative development and validation of an HPLC/DAD method for the qualitative determination of major cannabinoids in cannabis plant material” reference [1], see section 1.1; reports that THC-B is another form of THC acid that appears only in trace amounts in cannabis plant material. This article also reports other substances in cannabis plant material, including cannabidiolic acid (CBDA) and cannabigerolic acid (CBGA); a substance cannabinol (CBN) is also reported present in aged cannabis. 
THC acid may be converted into the psychoactive substance Tetrahydrocannabinol (THC), also known as (Δ9-THC) through processes that decarboxylates the THC acid. Decarboxylation is a chemical reaction that converts an acid to a phenol and releases carbon-dioxide (CO2) as a carbon atom is removed from a carbon chain.
Reference [1] also discusses and shows the decarboxylation of THC acid into Δ9-THC, the decarboxylation of cannabidiolic acid (CBDA) into cannibidiol (CBD), and the decarboxylation of cannabigerolic acid (CBGA) into cannabigerol (CBG). Decarboxylation occurs when cannabis is exposed to heat, light, cofactors or solvents.
Historical and anecdotal reports of the medicinal use of cannabis date back for millennia, in recent decades the psychoactive ingredient A9-THC has been extracted through a verity of processes; to date processes that decarboxylate of THCA-A into psychoactive Δ9-THC in controlled ways use toxic solvents; frequently a distillation process such as fractal distillation is then used to separate the toxic solvents from the active ingredient after decarboxylation. THCA-A decarboxylated into Δ9-THC in controlled ways using toxic solvents:
Related U.S. Pat. Nos. 6,365,416 B1 [2], 6,730,519 [3]; and patent publication US 2002/0039795 A1 [4] by Elsohly et. al. isolates Δ9-THC from cannabis base material using toxic non-polar organic solvents such as hexane, heptane, or iso-octane. U.S. Pat. No. 6,730,519 [3] was sponsored by a National Institute for Drug Abuse, Small Business Innovative Research grant; Related US Patent disclosures U.S. Pat. Nos. 6,365,416 [2] and 6,730,519 [3] in their Background of the Invention section provide excellent details regarding the medical use of Δ9-THC. the inventors conclude that extracting Δ9-THC from cannabis plant material is more cost effective than synthetically created FDA approved medicinal THC, and they reference prior art dating from 1942 through 1972 that relate to THC extraction or analysis of hashish and “red oil”; the processes referenced frequently use toxic elements such as carbon tetrachloride, benzene, N-dimethyl formamide/cyclohexane, or hexane.
U.S. Pat. Nos. 7,524,881 B2 [5], and 7,592,468 B2 [6] Goodwin et. Al. discloses processes that extract Δ9-THC from cannabis plant material; this process converts THC acid into salt using non-polar solvents such as pentane, hexane, heptane, or octane; again toxic or flammable solvents are used.
U.S. Pat. No. 7,344,736 B2 [7] and US Patent Application Publication US 2008/0167483 A1 [8] by Whittle et al (assignee GW Pharmaceuticals) entitled “Extraction of Pharmaceutically Active Materials From Plant Material” describe the use of liquid CO2 to extract cannabinoids including THC and CBD from cannabis plant material.
U.S. Pat. No. 7,622,140 B2 [9] and US Patent Application Publication 2010/0119606 A1 [10] by Whittle et at (assignee GW Pharmaceuticals) entitled “Process and Apparatus for Extraction of Active Substances and Enriched Extracts from Natural Products” describes the use of high temperature gas to extract cannabinoids including THC and CBD from cannabis plant material. US Patent Application Publication US 2003/0017216 A1 [11] by Schmidt et al entitled “Isolation of Herbal and Cannabinoid Medicinal Extracts” describes that solvent extractions of cannabis for durations less than 5 minutes yield extracts of higher quality as they contain fewer non-therapeutic materials than extracts of a longer duration.
Throughout the balance of this disclosure the term medicinal cannabis compounds refers to cannabinoids in their decarboxylated state, in the acidic state, or in combination thereof. For example medicinal cannabis compounds include yet are not limited to Δ9-THC which is decarboxylated THC acid.
Cannabis is a high priced commodity, high quality cannabis wholesales today for around $3000 per pound and retails for around $6000 per pound ($375 per ounce). Because of this high valuation an extraction derived from a large amount of cannabis in concentrate is a target for theft and abuse.
California collectives and cooperatives are authorized to grow cannabis by state law for medicinal use. They are located throughout the state and are often separated by dozens or even hundreds of miles. The main products they provide for medicinal use are cannabis flowers commonly called buds. These flowers contain the greatest concentration of medicinal compounds, some varieties of cannabis buds contain 20% to 25% or more medicinal cannabis compounds by volume.
Cannabis plants also contain leaf and stems that are not typically utilized as medicinal cannabis , yet are typically used as mulch or fertilizer for growing other cannabis plants. This is because there is little to no market for leaf or stems because medicinal cannabis patients do not prefer leaf or stems. Leaf matter contains about 8% to 10% medicinal cannabis compounds by volume. Utilizing this as mulch wastes the medicinal cannabis contained within. California law also stipulates that cannabis be controlled and not used for non-medical use. Utilizing leaf matter as mulch may be considered by some as a non-medicinal use of cannabis, and may be in violation of California law. Another concern for lawmakers is the diversion of cannabis grown legally into illegal or illicit markets.
Extracting medicinal cannabis compounds from cannabis leaf matter eliminates waste and enables growers to control cannabis in accordance with State laws. The invention described within this disclosure is an apparatus and process that extracts medicinal compounds from cannabis plant material in large volumes, yet stores the extraction in a large volume of solvent. The invention eliminates waste and prevents diversion of cannabis into illegal or illicit markets by neutralizing cannabinoids within plant material.